This invention relates to radiation curable prepolymers, reactive diluents for incorporation in formulations containing said prepolymers, cured products prepared therefrom, and processes relating to the preparation and use of said reactive diluents and of the formulations containing them.
Radiation cured polymeric systems containing occasional sulfur linkages are known and are desirable because of the fact that they are normally tough, flexible films. The majority of these systems have been based upon a curing reaction between a thiol function and a vinylic double bond function in the precursor molecules, the so-called "thiol-ene" reaction.
The use of reactive diluents containing preformed thiocarbamate linkages to increase the toughness and flexibility of radiation cured polyurethane films while improving the processing characteristics of uncured formulations containing them has not been reported. Indeed, the known sensitivity of many types of carbon-sulfur linkages to ultraviolet light makes the usefulness of the compounds of this invention as reactive diluents for radiation curable polymers even more surprising.